I made a dry storage and feed box for my filament that sits beside the printer. This way I can keep unused filament clean and dry and easy to change over to a different type. This is an 80qt. Sterilite air tight box with a steel rod to support 4 spools (could fit 5 regular spools). Feed through flanges pass the filament outside to a shared filament guide tube that feeds into the back of the printer enclosure. Inside the enclosure frame is a filament filter. On the box lid are some open cell foam blocks that create some drag on the spools to prevent over rotation and unspooling of the filament: